考虑腐蚀的埋地灰口铸铁管失效预测及可靠度分析  

Failure prediction and reliability analysis of buried grey cast iron water mains considering corrosion

作　　者：邵煜[1] 张土乔[1] 俞亭超[1] 

机构地区：[1]浙江大学土木工程学系,浙江杭州310058

出　　处：《浙江大学学报（工学版）》2010年第1期160-165,共6页Journal of Zhejiang University：Engineering Science

基　　金：国家自然科学基金资助项目(50708091);教育部新世纪优秀人才支持计划资助项目(NCET-04-0525);国家水体污染控制与治理科技重大专项资助项目(2008ZX07425-008)

摘　　要：针对早期埋设的灰口铸铁管存在的破损频繁、漏失严重等影响输配水安全问题,通过管土相互作用模型得到管道应力,应用腐蚀模型预测管道腐蚀深度,进而评估管道的剩余强度,结合失效准则得到管道失效预测模型,并运用蒙特卡罗方法对管道可靠度进行分析.计算模型充分考虑了管道腐蚀、各种外部荷载以及参数的不确定性对管道失效的影响.计算结果表明,在通常荷载作用下仅考虑管道受力,管道不会失效,腐蚀是导致管道失效的重要因素;管道安全因子的概率密度分布曲线呈对数正态分布;当使用时间为20～50a时管道失效风险较大,在使用时间超过80a之后,管道失效风险变小且呈现出略有下降的趋势;由于渗漏或不均匀沉降引起的管道基础局部流失在腐蚀深度超过一定值时对管道失效概率的影响较大.To resolve the serious breakage and leakage problems for the grey cast iron water mains buried in the early years in the water-supply system,pipe stresses were firstly calculated based on the pipe soil interaction model,and the corrosion depth was predicted by the corrosion model.Then,the residual strength associated with corrosion was evaluated,and a failure prediction model was given by using the failure criterion for the cast iron.Monte Carlo （MC） simulations were used to perform the probabilistic analysis.The given model fully considers the influences of corrosion,external loads and uncertainties on the pipe failure.Results show that the pipes will not be failed when only considering the external loads.The corrosion is one of the very important factors contributing to the pipe failure.The probability density distribution of the safety factor of the pipe appears a lognormal distribution.The hazard of the pipe failure is large in 20-50 years,and it becomes small after 80 years and decreases with the time.The influence on the failure probability is large for considering soil bedding lost induced by the breakage or uneven settlement when the corrosion depth reaches a certain depth.

关 键 词：管土相互作用 腐蚀 剩余强度 灰口铸铁管 失效预测 可靠度 

分 类 号：TU991.36[建筑科学—市政工程] TB114.3[理学—概率论与数理统计]